A multipoint lock typically comprises a central lock and one or more remote latches. The remote latches are operated by operation of the central lock and the remote latches are attached to the central lock via a slide member. This general type of multipoint lock is well known.
The multipoint lock provides improved security to a door by allowing the door to be locked at 2 or 3 spaced apart locations as opposed to a single location. Typically, the central lock is positioned on the door at a normal position and each remote latch is positioned adjacent an upper or lower part of the door.
While multipoint locks provide advantages, fitting of a multipoint lock to a door or window is more complicated than fitting a single lock. One difficulty is that if a pair of remote latches are provided, the latches are “handed” which means that the correct latch must be placed adjacent the top and bottom of the door. Sometimes, the latches are fitted the wrong way round which means that the multipoint lock does not work.
Another difficulty with multipoint locks is attachment of the slides or rods to the central lock and to the latches. The attachment is often finicky and difficult. Also, repair and replacement of multipoint locks can also be quite finicky and difficult due to the difficulty in attaching and releasing the slide or rods, which extend from the central lock to the latches.
Another major disadvantage with multipoint locks is that the central lock needs to be designed specifically for a multipoint lock arrangement. This means that if a multipoint lock is not required, the central lock cannot be used. Therefore, there would be an advantage if it were possible to have a central lock which could function either as a conventional solo lock, or as a multipoint lock.
Australian patent 714689 describes a multipoint lock. The multipoint lock has an internal sliding or rotating deadlocking member. The deadlocking member has a transversely extending finger portion which extends to the rear of the lock. The transversely extending finger portion engages with a pin on an external slide. Thus, movement of the deadlocking member allows the finger portion to push against a pin which can result in operation of the remote latches. However, movement of the deadlocking member in the opposite direction does not result in operation of the deadlocking member. In an attempt to overcome this disadvantage, the same patent describes a further embodiment where the finger portion contains a slot which traps the pin. Therefore, movement of the deadlocking member in either direction can operate the slide. A disadvantage with this arrangement was that the slot has a degree of “lost motion” which means that some movement of the deadlocking member does not result in corresponding operation of the remote latches. Another disadvantage was that the slide was only loosely held and was not fixed to the deadlocking member.
It will be clearly understood that, any prior art publications and referred to herein, does not constitute an admission that any of these publications form part of the common general knowledge in the art in Australia or in any other country.